Remote control for displaceable objects



Dec. 7, 1948. c. H. DEDERICK REMOTE CONTROL FOR DISPLACEABLE OBJECTS Filed April '21, 1941:

5 Sheets-Sheet 1 .K: 0 l M/ K /Av M: 5 k m 8/ J M y o M a W 2 5 C. H. DEDERICK REMOTE CONTROL FOR DISPLACEABLE OBJECTS 5 Sheajzs-Shet 2 Filed April 21, 1943 //\l r/fzvro z CLINTON 1-1 0505mm, WZW V 412 Dec. 7, 1948. c, DEDER|K 2,455,568

REMOTE CONTROL FOR DISPLACEABLE OBJECTS I Filed April 21, 1943 i 5 Sheets-Sheet s 1 260 I g 205 i a Z 84 7 I60 i /A l EA/TOE.

Dec. 7, 1948. c. H. DEDERICK 2,455,568

REMOQI'E CONTROL FOR DISPLACEABLE OBJECTS Filed April 21, 194:5 5 Sheets-Sheet 4 tun/Tow #060591 Patented Dec. 7, 1948 UNITED STATES PATENT OFFICE REMOTE CONTROL FOR .DISPLACEABLE OBJECTS Clinton '11. Dederick, Brentwood, Mo., assignor to The Emerson Electric Mfg. Company, St. Louis, Mo., a corporation-f Missouri Application April 21, 1943, Serial No. 483,903

ZS-Claims. l

"I'his invention relates to a remote control'for a displaceable object. .For example, it can be used to producemovement in either of opposite directions for the device to be positioned, such as a trimmer tab on an aircraft.

The. mechanism includes a control which may be preset and which operates a reversible motor in one of its directionsa distance determined by the presetting. of the control- Provisions are also made to prevent override .of the, motor .beyond the normal operating limit in either direction.

An object of the invention is to provide such aeontrol by which. an object to be'positioned may be positioned ata proper point and .may be displaced in either direction from that point.

More specifically, an: object is to provide a convenient automatic remote control for positioning trimmer tabs on. aircraft.

More specific objects. include theprovision of a motor with a power take-off foreoperating the device to be positioned, and with a compact and accurately operating. form of limit control-to prevent. the motor from moving. the device beyond its normal maximimillmits.

Afurther object is to provide acombinationof suchamotor with a control which may :be .preset to determine the extent of movement ofthe motor and, consequently, of thedeviceto be-displaced whereby the motor may operate to such extent and stop.

-A further object is the provision of a control of this type in combination with'a motor means, in which the mechanism is provided-'with'full voltage throughout the entire range of operation.

A further object is to provide a control .and motor means of this type, in which constant torque is obtained throughout the operation.

Aiurther object is to provide a. combinationhaving connections causing the motor "means to. avoid override, and specifically to cause the motor means .to have a dynamic brakingefiect.

An .object istoprovideacontrol. and motor that may graduate to a selectable. fine degree, and which will operate accurately .insuch -fine degree.

In the drawings, the motor and. controlaiare shown in two-separate units, although they-may be joined together, ifdesired.

Referring to the drawings:

Fig. '1 (Sheet .1) is arsideelevatiomo'f the mo.- tor'unit looking toward the .poweroutlettherecf Fig. .2 is a side elevationiof. .thezlower'side'shown inFig. 1;

Fig. 3 is an end elevation from the right-hand end in Figs. 1 and 2;

Fig. 4 is an end elevation from the left-hand end of Figs. 1 and 2;

Fig. 5 is a transverse section through part of the power take-off on the line 5-5 of Fig. 1;

Fig. 6 (Sheet 2) is a longitudinal section on the line 6-5 of Fig. 1, part being eliminated;

Fig. 7 is a. view from the bottom side of Fig. 2 with the cover removed;

Fig. 8 is a longitudinal sectional View taken on the line 8-8 substantially through the middle of Fig. 6;

Fig. 9 (Sheet 1) is a section taken on the .line 9-9 horizontally across the top part of Fig. 6;

Fig. 10 is a view of an actuating rider for the limit switch in the motor housing:

Fig. 11 is an end view of that rider;

Fig. 12 (Sheet 2) is an end view of the carrier for the limit switch;

Fig. 13 is a side view of that carrier;

Fig. 14 is a bottom view of the carrier;

Fig. 15 is an end view of the tripping actuator for the limit switch;

Fig. 16 is aside viewthereof;

Fig. 17 is a view of one of the adjusting elements for the limit switch;

Fig. 1-8 is a bottom view thereof;

Fig. 19 (Sheet ,3) is a View of the dial of the control;

Fig. 20 (Sheet 4) is a plan view of the control;

Fig. 21 is a side view of the control;

Fig. 22 (Sheet 5) is a vertical section through the control, medial to the back plate, taken on the line 22-2 2- of Fig. 20;

Fig. 23 is a vertical transverse section, taken on theline 23-23 at the left of Fig. 21;

Fig. 24 is a section on the line 24-24 at the left of Fig. 21;

Fig. 25 is a section on the same line as Fig. 23, looking in the opposite direction as indicated by the arrows 25-25 of Fig. 21;

Fig. 26 is a section on the line 26-26 toward the right of Fig. 22;

Fig. 27 (Sheet 4) is a view of a cam follower and switch actuator;

Fig. 28 is a section on the line 28-28 at the right of Fig. 21; and

Fig. 29 is a wiring diagram of the mechanism.

The mechanism includes a main motor housing 30, in which there is disposed a reversible electrical motor of cheer the familiar types,v preferably shunt wound to provide dynamic braking. To the housing 30 is secured a power take-01f extension'or gear case 3|, from the side of which M there extends a drive member 32 that is reciprocated by mechanism operated by the motor.

Referring to Figs. 6, and 8, the motor drives a shaft 33 to which is secured a worm 3 1. This worm meshes with and drives a gear 35 fixed to a stud shaft The shaft 3'6 is rotatably mounted in bearings 31! and 3 8 in the box 3i. A suitable cap 39 is provided to give access to this shaft and to the attached mechanism.

At one end of the shaft 35, there is secured a gear 42 (Figs. 5 and 9) that meshes with a larger gear 43, which is mounted upon a shaft M supported at its smaller end in the extension 3i, and at its other end supported by bearings 45 and lt, respectively, in a cover plate 4? bolted (Fig. l) to the extension, and in the extension itself. The shaft i l extends through the plate M.

It will be seen from the foregoing that rotation of the motor will cause rotation of the shaft 44.

but that the latter will rotate at a much lower speed than does the motor.

As shown in Fig. 29, the motor is indicated at 3B, and the gearing generally indicated at G. The shaft M. is shown projecting from the gear box, and it is threaded. through a nut 32 Which is held against rotation, so that the nut 32 is reciprocated along the shaft M. upon rotation of that shaft. This is simply the familiar jack screw arrangement. The nut operates through linkage 5c and 5! to a trimmer tab it? pivoted at one edge 53, to the Wing of an airplane. It will be seen that the trimmer tab is positioned upon rotation of the motor shaft, and that its degree of angularity depends upon the position of the nut The shaft M at its smaller end operates a makeand-break switch (Figs. 6 and '7). To this end, the shaft has a portion that extends into a recess 55 formed in the extension SI. The portion 55 of the shaft is fiatted on two sides and extends, as shown in Fig. 7, adjacent a spring switch blade 57?. The blade 57 is mounted as shown upon the insulating plate 58 in the recess 55, and is grounded. The blade 57, by its spring action, normally urges its free or upper end in Fig. '7 toward the center of the shaft M. Consequently, the blade 5i will normally engage the flats of the portion 55 of the shaft, and will be displaced to the right (Fig. 7) each time the shaft rotates one of the flats away from the blade.

A second switch blade Bil is likewise secured to the plate 58 and normally insulated from the blade ill. The blade Ell has a portion extending around the shaft and presents a contact 6| which is engaged by the contact 59 whenever the blade 51 engages one of the flats on the shaft.

In its intermediate portion, the shaft 44 is threaded at 65.3. The T-shaped nut or rider 48 (appearing in detail in Figs. 10 and 11 of Sheet 1) engages over the threaded portion 62. The stem part 64 of the member 48 is flat and engages against an inner wall on the extension 3!. This prevents the rider ll from rotating upon rotation of the shaft, but permits it to move axially upon such rotation. The member 48 has two wings 86 and 5?.

A tripping member 68 is pivoted upon a shaft til secured to the extension 3I. This member appears in section in Figs. 6 and 8 and in detail in Figs. 15 and 16 (all on Sheet 2).

The tripping member 63 is divided by an angular cut-out into two ends Ii and i2. Transversely, it is also divided by an arcuate cut-out it which, as shown in Fig. 6, may accommodate the shaft cl l. This cut-out "l3 divides the extensions ll and I2 each into two parts. The portion 7! has the legs lid and lib. The portion I2 has the legs 52a (Fig. 6) and I211 (Fig. 16).

The arms fit and 61 on the T shaped rider 48 will engage the arms Na and I lb when the rider is displaced to an extreme upper position in Fig. 6, and will engage the arms 12a and 12b as it appreaches the extreme lower position in Fig. 6. At intermediate positions, the arms 66 and 6! will not engage either set of legs; and, owing to the sloping edges of the legs, the displacement of the tripping member 68 will increase as the movement of the rider 48 toward either pair of legs in- The member 68 may be provided with a notch l5. A small leaf spring l6 is in such case secured to the box 3I and engaged in this notch "I5. This leaf spring yieldably maintains the tilting member Bil in a neutral position, so that its axis is parallel to the axis of the shaft 44. In this neutral position, the nut 48 may move back and forth through a considerable range without tilting the member 5&3. Beyond these limitations, it will begin to displace the member 68 by contact with the sloping surfaces thereon and after a certain degree of such tilting, will operate the limit switch mechanism, now to be described.

The limit switch mechanism, actuated by the tilting member 68, comprises two limit switches and 8!. These limit switches are the same in construction, so only one need be described. The limit switch 8| appears in Fig. 8.

Each switch is provided with a U-shaped bracket 82 (Figs. 8, 12, 13, 14). This bracket 82 comprises two legs joined by a bight portion 83. A pivot shaft 85 is secured in the extension 3i and passes through openings 86 in the ends of the legs of the member 82. It also passes through the housing of the limit switch.

Legs of the member 82 are also provided with pairs of openings 81 to receive a rivet 88 through the limit switch housing. The pivot 85 and the rivet 88 keep the switch firmly held in the bracket 82. The limit switch unit 89 has a spring blade 90 pressing against a button 9| and urging it toward the member 68. The blade 98 is also connected at its free end, by an overcenter spring 92, with a spring switch blade 93. The blade 93 has a double contact 9 engageable with either a fixed contact or a fixed contact 96. When the button SM is free, the spring 90 will move toward it, causing the overcenter spring 92 to move the switch blade 93 to close its contact 94 with the fixed contact 95. Upon pressing of the button by the member 68, the spring 90 will move out, displacing the spring 92 overcenter, and causing the blade 93 to shift its contact 94 to engage with the contact 96.

The U-shaped member 82 has a slot I04 on the bight portion 83 thereof. This slot is engageable by an eccentric pin I05 on a disc I06 (Figs. 8, 1'7, and 18, Sheet 2) integral with a short shaft I01. This shaft is secured in the wall of the extension 3| and has mounted thereon a pointer I08 and a hexagonal head I09 by means of which the pointer may be turned, and with it the pin I05. The pointer cooperates with indicia (Fig 2) on the member 3I.

By turning the head M9, the pin I05, acting in the slot I 04, displaces the U-shaped member 82 about the pin I05 and causes the button 9| to approach toward or recede from the member 68. This will adjust the point of travel of the member 68 at which the limit switch will be tripped. A similar operating head III) with a pointer and indicia are provided for the limit switch 80. By

enema-6e moms :ofithese .two members 109 wand 1 I0, the range-of free'operation 0f the-nut 64 is "controlled. In tum;:the scope of .operation orthe operating mechanismzi'z is controlled.

'lr'lhelimittswitch w also has a.=simila'r movable contact III, normally engaging ea fixed contact H2, butLdlsplaceable.to'aifixed contact II'3.

. AJcapII I covers the'endtofthemember 3| and .receives a connection plug H6 by which the wiringmay be'ibrought into the'imechanism.

The control'portion'of this mechanism is shown .particularlypnrsheets 3, 45and 5. .A panel I omnprises a wall to-which: the controlmay be attached. The plate I 25.is.:preferab1yof'insulative material. It has an 'openingtoreceive .a flanged member I26 iathat is circular and to which are secured aiplurality of rods I21 by means'of which the elements of the control are supported. The member :I26 has 'a cylindrical Lfro'nt plate I28 having apointer I2-9 onL-the-edge thereof.

The several 'ro'ds I21 support a'forward disclikeplate I30, a cut-away disc-like plate I3I,.a :back-centertplate I32, and a back plate I33.

The control mechanism operates from a center tubular shaft I "that is supported directly or indirectly'in .the transverse plates. This shaft "511s adapted'to be manually displaced from a .neutralposition :and automatically returned to that neutral position. In this operation, the shaftiseaxially displaced, a dial is turned, as will appearyand likewiseta'pointer is turned.

Tofaccomplishthe foregoing, a cup-like member I86 has a center bearing portion 131 supporting the shaft I35 "for rotatable movement,

the portion I31 in turn, bearin in an opening with theplate I26 Jforits own rotary and axial movement. This cup-like member is enclosed by :a transparent plastic sheet I39 upon which is mounted .a knob I40. It will be seen that by pressing the knob to theright in Fig 2, the cup-like member I36 will be displaced to the right, and thatzby turning the knob, the cup-like member maybe turnedrelative to the shaft and vthe'member-IZG. .The cup-like member has on its outer surface-a fdial I38 with which the previouslyxmentione'dpointer I29 registers.

Withinithe cup-like member there is a pointer [42 that is secured to'the-shaft I35.-and rotates therewith. This pointer I42 may comprise a mark on a disc.

Inward'pressure on the knob is opposed by 'a spring I43 acting between a flange on a cup-like member I36 and'the end of the cylindricalportlon I26. This spring normally maintains the cup member- I36 outward.

'As appears, the bearin portion I31 of the member- I36 extends through the plate I26. On the inner end of the bearing portion I31, there is secured a toothed wheel I46 (Fig. 23). The toothed wheel I46 is normally held toward the .plate I26'by the springl43. In this position, a restraining member I41, secured to the member I26 engages between two of the teeth and preyents-rotation'of the member I46 and the cuplike. member I36 to which it is attached.

"The wheel I46 also has a tooth I50 extending from lts'iace (see the lower left portion of Fig. 20 and thenine-oclock position on Fig. 23). This tooth I50 is-adapted to be brought between ad- Jacent teeth of a'toothed wheelI5I that is fixed to the shaft 135. Such engagement takes place when the knob I is depressed to move the toothed member I46-inwardly'until it is free of theres'training member' I41 and until the toothed member I makes its engagement with the' member 'I5I. Th'ereupon, irc'itatlor'ioof tlrelmob I40 will'rotate theILcup-shaped member f36,"th"e wheels I 46 and I I5 I to "displace the *shaft 1" I' 35 th'e distance indicatediiby .the pointer "I29 "against": the dial I38. '-When the;fshaft=- is-"r0tated Ithe .rles'i'r'e'd distance, theieknobr I40. is released' whereupon the member I46 and the cup member I36 return 'I-to their outward positions in "which they are retaine'd-byengagement of 'the'imember I41 with the toothed member 146.

.During the 'se'ttingctoperation -a-lso,"the .sfpointer 142 will have "followedtheij oint :displacement :or the cup-shaped'member I'36t-andtthesshaft I 35. From an initial:=zero starting position on the dial, thewpointerl Ir42= will :not :be displaced withrlespec't to the 'dial when'the zero position 101' the "dial itself 1' is :angularly 'mov'e'cl. :However, as williappear, a return-of theishafti I 35't0 itsneutralJposition will carry thepointerw'ith it without moving thedial; 'sotth'at the :pointer' indicatesoat all'stimes the position ofx'the' shaft I35.

'A spring :ty'pe: retaining'mea'ns 'I 52 .tcompi'isin'g a sprin'ge'pressed 'iarim I53 havinga roller 154 thereon .for engagement between adjaeentiteeth 1 to themember I 5I -is I secured Tto the supporting plate I 30. This prevents :fortuitous displacement of thefshaft.

.Thetoothecl wheel iIi5I :is -patt of .v a stepping means :to return the shaft to itsineutral'sposltlon. This stepping means c'o'mpri's'esva counterclock wise stepping magnet I51 and .a cl'ockwise'steppingimagnet I58. When employed oniai'trimmer tab, the magnet I51 will ultimately .controla turning of the trimmer tab up and themag ne'tiIfl will control turning .of the trimmer :down.

'The .magnets are similar. The magnet I 51 has. a coil I 59 supportedion'a bracket I 60secure'd to the supporting :plate II 31. The bracket I605. in turn has an overhanging extension rI6I that limits upward? movement .iof an armature "member "I62 :pivote'd .onto l the *fibra'cket I60. :This armature member carries flan extension 163 that is adapted to'loe "brought do-wn'to engage :a toothof the wheel I5I an'd move the wheel the space of one toothi'f'orseacherrerglzation*of'the coil "I5 9. This action of =-the armature IE2 is opposed by a-sp'ring 'I64 which mai'nta'insthe extension- I63 away :rrom the wheel I5I whenever the coil is de'ene'rg-ized.

Similarly, the 'magnet 150 'has 'acoil 'I-65J:supported by a similar braeket -l -66 having anrextension I'61,'an armature member I68, ameXtensi'on I69; and a return spring I 10. 'The'extension lfifl engages the wheelI'5'I on the side 'o'pposite the extens'lonfl 63 so that it may rotate the wheel; in the opposite direction th'e fdiSt2.I1C8-..Of one tooth for each energization of the coil.

The: operation: of the motor'ias *well' as that of the coils I53 and 1654's controlled by a cam I15 that is fixed to the'shaft I35.

The cam I15 has opposite rises I18 and I19 thereon (Fig.6). "Between these rises'the cam comprisesa low edge I and a'high edge IBI.

combination switch :actuator and cam follower I82 is actuated ibyoneasi'deof the cam,.an'd a similar follower-and actuator I83 is actuated by the other =side.of:the cam. These actuators are shown more in detail in Figs..26 and2'1. They are'the same in'construction. Describing the member I 02; it includes a follower portion I 84-, struckback to :engage'ithe cam, and :two switch actuating portions I85 and I186. The nrember I82 is ilikewise attached at its bottom to -a U eshapedibracket l-i8'1thr-ough the earsaof which extends a-.:pivot.shatt:-t88.

In like manner, the member I83 has a follower portion I89, two switch actuating portions I90, and is secured to a bracket I9I the ears of which receive a pivot shaft I92. As appears at the bottom of the right center of Figs. 21 and 22, the pivot shafts I88 and I92 are secured to the plate I32.

From the foregoing, it will be seen that if the cam I15 is rotated clockwise in Fig. 26, which is counterclockwise on the dial in Fig. 19, the rise I18 will displace the member I82; whereas, the member I83 will notbe displaced as its follower will remain on the low edge I80. The cam is capable of nearly 180 of movement, in each direction. It will also be seen that such displacement of the member I82 will move the upper end of said member outwardly from the shaft I35. Counterclockwise rotation of the cam will similarly displace the follower I83.

The switch actuating portions of the members I82 and 183 actuate four snap-action single-pole double-throw switches. These switches are the same in construction as the limit switches BI and 82, and, therefore, need not be described in detail. Suffice it to say, that as appears in Fig. 26, each such switch has a button I94 engaged by one of the switch actuating extensions of the members I82 and I83. Such buttons are shown also in Fig. 28, and in these figures, it will be seen that these various switches all include a spring blade acting against the button, a bowed over-center spring, and a spring contact blade, having a double contact on it, alternately engageable with two fixed contacts.

In Figs. 20 and 28the rearward switches I96 and I91 appear. The switch I96 has a doublethrow contact I98, normally engaged with a fixed contact I99, but moved into engagement with a fixed contact 200 upon operation of the cam I15 to displace the follower member I82.

The switch I91 in similar fashion comprises the double-throw contact 2!, normally engaging a fixed contact 202, but movable against the fixed contact 203 when the cam I15 is moved to displace the follower member I83.

The forward switches are identical with the rearward ones, and comprise switches 204 and 205, the former also operated off the follower I82 and having the double-throw contact 206 normally engaging the fixed contact 201, but displaceable against a fixed contact 208 upon movement of the cam I15 to displace the follower I82. The other switch 205 includes the double-throw contact 2II normally engaging the fixed contact 2 I2, but displaceable against the fixed contact 2I3 upon rotation of the cam I15 to displace the follower member I83.

Thus it will be seen that the switches I96 and 204 are operated by the follower I82, and the switches I91 and 205 are operated by the follower I83.

The shaft I35 is hollow. Through it runs a rod 2 I6 (Fig. 22) which is axially movable within it. This rod at its outer end may engage against the crystal I39 behind the knob I40. At its opposite end, the rod 2I6 has a head 2I1 for actuating an additional single-pole double-throw switch, generally indicated at 220. This switch is attached by brackets 22I to the supports holding the several switches I96, etc., to the plate I32. The switch 220 is similar to those previously mentioned, being an over-center switch operated by a button that may be engaged by the head 2 I1. This button in turn operates a double-throw contact blade having its double contact 223 norswitch.

sol

mally against a fixed contact 224, but displaceable against a fixed contact 225 whenever the rod 2I6 is moved inwardly, which will occur whenever the knob I40 is displaced inwardly. The switch will be released to its starting position whenever the knob is released.

A further switch generally indicated at 221, is secured to the back partition I33. This switch comprises a spring blade 228 having a contact 229 that is brought against a contact 230 fixed to the partition I33 whenever the rod .2I6 is moved inwardly. As will be seen, an insulating button extends from the blade 228 against the spring blade of the switch 220. The switch 221 need not be snap-action, and it will return to open position upon release of the knob I40.

An additional coil 235 is supported upon a bracket 236 secured to the partition I32. The coil 235 actuates an armature comprising a switch blade 231 to bring it against a contact 238, or to release it against a contact 239, these elements comprising a switch 240. As will later appear, the coil 235 may be energized through the switch 221.

A main switch .244 for the mechanism is mounted on the back wall I33. It includes a contact 245 mounted on a spring blade and a contact E46 mounted on another spring blade. These spring blades are secured to the back partition I33. The switch 244 is adapted to be actuated by a rod 241 slidably supported in openings in the top of the partitions I30 and I32. This rod extends into a cut-out portion 248 in the member I26. At its forward end, it projects to immediately behind the dial member I36, and is pivotally connected to a lever button 2 29, which lever is pivoted to the flange I28. When the upper end of the lever 249 is depressed toward the back of the instrument, the rod 241 will be shifted forwardly to permit the switch 2 14 to open. Op.-

posite displacement of the lever will close the Also depression of the knob I40 will close the switch by engagement of the dial member I38 with the end of the rod 241. The switch is maintained in either position by the engagement of a spring supported roller 250 in either of two notches 251 on the rod 241. The roller 250 is supported by its spring 252 onto the partition I32.

In Fig. 29 is shown the wiring diagram demonstrating the manner in which the control and motor are connected. In this diagram, the cam operated switches have been separated, and the cam indicated four times, although, obviously,

I it is more economical to use the single cam shown in the other drawing. Also the cam rises have been exaggerated for clarity of the drawing.

In Fig. 28, the battery, or other source of power, is shown at 260. One side of the battery is grounded, and the other side leads by a line 'ZBI to the switch 244, which, it will be remembered, is the one actuated by the lever 2 19 at the top of the control panel. From the switch 204, a line 262 extends to a junction whence it divides into a line 283 and a line 264. The line 263 extends to the contact 228 of the switch 220, this being the double-throw switch actuated by the rod 2I6 when the knob I49 is depressed. The other terminal 225 of the switch 220 is connected by a line 265 to ground. This line 265 likewise is extended into the motor switches as will be described. The blade of the switch 220, with its double contact, is connected by a line 266 into the motor switches and the stepping coil switches, as will appear.

Returning to the line 264, this line extends 2,45s;see

through a shunt winding 261i of the motor, and thence by a line 268 is grounded; A branch'269 (top of Fig. 28) from the line'264extends through the coil 235, which, it will be remembered, is disposed at the bottom of the control. The other lead 210 from the coil 235 extends to the switch 221, which, it will be remembered, is closed upon depression of the knob and displacement oi the rod H6. The other side of the switch-2'2! is grounded.

The line 210, likewise, is connected to the-contact 238 of the switch 240. The movable blade of this switch is permanently connected by a line 2' tothe'switch 51, which is in turn grounded. The other contact 2390f this switch is connected by a line 212 with the'stepping magnets, as will appear.

The shaft I35 upon rotation displaces the cam to move the four cam switches. Assuming that Fig. 28 is taken from the front of the control, the left-hand switch is 204 and the second I96. The inner right-hand switch is I91 and the outer right-hand switch is 205.

The line 265 leading from the contact 225 of the switch 220 in the-upper left of'Fig. 28, branches into a line 213 connected to the contact I99 oftheswitch I96, and into a line 214 oonnected'with the contact 202 of the switch I91. The other contact 200 ofthe-switch I96 is com nect'ed by a line 215 with the line 266; and the other contact 203 of the switch I9 Iis connected by a line 2'16- with the same line- 266.

The double-throw contact I98 of the switch I96 is connected by a line 211' with the normally closed contact 95 of the limit switch SI in the motor housing. The double-throw contact 94 of this limit switch is connected by a line 218 into the rotor of the motor 30. The other contact 96 of the limitswitch 8| is connected by a line 219 to ground and to the contact II3= of the other limit switch 80. The movable contact III of the limit switch 90 is connected by a line 280 of the rotor of themotor 30; The normally closed contact I I2 of'thelimit switch 80 is connected by a line 28l:to the double-throw contact 20I of the motor cam switch I91.

The power line 266 is likewise connected into the stepping magnet switches 204 and 205. A line 282 connects the line 266 with the contact 201 of the switch 204. The movable contact 206 of the'switch 204 is connected by a line 283 with the movable contact 2|! of the-switch 205. The other contact 208 of the switch 204 is connected by a line 284 to the coil I59. The other lead 205 from the coil I59 is connected both to 1 the line 212 and tothe coil I65. The coil I65 in turn isalso connected by a line 280 with the contact 2I3 of the switch 205'. The contact 2| 2 of the switch 205 is directly connected to the line 249.

Operation The control at the start has the shaft I35 in neutral position and the dial registering zero against the pointers I29 and I42. In this position,.the knob I 40,is.released so that the switch 226 is closed against the contact .2 24. The switch 22] is openand switch 244 is normally'open. The cam switches are "m the positions shown in Fig. 28., as well as in the, other figures. The switch 240 is in the position shown. The switch 51 may be opened. or closed depending upon the more or less fortuitous position. of. the motor 30, and the limit switches 80 and 8| are in the positions shown in Fig. 29; In this case, too, the mechatheiroriginalpositions.

l0 nism to be actuated will be in a neutral position, which, in the case of thetrimmer tab, means at zero angularity relative to the airfoil.

The first operation is to depress the knob I40. This action will inter alia, close the main switch 244 by engagement of the dial members 136 with he rod 247. The switch 244 controls the admission of" power from the battery 260 to the whole system. Immediately upon its closing, it brings power to the switch 220, the coil 235, and the field winding-261. As long as the rotor of the motor is out of circuit, the field winding 26'! acts as a dynamic brake to prevent rotation. The motor circuits depend'upon the introduction of power from the movable contact 223 of the switch 220 through the line 266, as will be described in more detail; The same may be said for the stepping magnet coils I58 and I59. Consequently, the shifting of the switch 220 upon depressing of the knob Hill-to break the contact 224 andto make the contact 225 cuts the motor and the stepping magnets away from power; and this condition is maintained so long as the knob is depressed. Since=the knob must be depressed to efiect rotation of the cams, and to rotate the dial, this breaking of these circuits is held until the dial is set to its desired position. Thereafter, upon release of the knob I40; the switch 220 will shift back to admit power to the motor and stepping magnet circuits in so far as they are closed other- Wise; However, the main switch 244 will be held closed by the detent- 250.

The rotation of the shaft I35 will displace two of the cam switches and leave the other two in Assuming that the shaft is rotated clockwise in Figs. 19 and 29, this will shift the switches 204 and I96 so that the former closes with the contact 208 and the latter closes with'the contact 200.

When the switch 264-thus shifts, at the instant the switch 220 is returned to initial position, the line 266 is connected to the battery. Owing to the-fact that the switch 205 is in neutral position, thebattery current is carried by the line 256 through the contacts 2I2 and 2H of the switch 205 to the line 283. Thence, it continues through the contacts 206and 208 of the switch 204 and by the line 284-through the coil I59. From this coil, itcontinues by the line 285 to the line 212 and the contact 239 of the relay switch 240.

If the motor had in a previous operation stopped with the switch 5'! closed, this stepping magnet circuit would be completed immediately upon release of the knob I40, were it not for the presence of the relay switch 240. It is, of course, the objective of this mechanism that the motor shall make a predetermined number of revolutions for each stepping action of the stepping magnets. Hence, were it not for the presence of the relay switch 240, the stepping magnet I59 might energize to step the shaft back oneunit of distance, the instant the switch 220'is returned, and prior'to any rotation of the motor itself;

As heretofore noted, the switch 22! is closed when the knob I40 is depressed, completing a circuit through the coil 235 and the switch 221. Such circuit through the coil 235 will lift the contact .23! from the contact 239 to the contact 238. This holds open the circuit heretofore described through the stepping magnet I59, and makes a holding circuit for the coil 235 in parallel with the switch 221; so long as the switch 51 is closed. This holding circuit will then remain closed after release of the knob and until the switch 51' is opened. When this switch 5'I'subsequently opens,

the holding circuit will break, deenergizing the coil 235 and releasing the armature to complete the circuit from the stepping magnet I59 through the contacts 239 and 23?, the line Z'II to the switch 51. When the switch Eil later closes, the circuit will be completed to ground for the instant of closure of the switch 5?. This will energize the coil I59 to bring the extension I63 down against the wheel I5! and displace the same the distance of one notch, this displacement returning the shaft I35 a corresponding distance toward neutral position.

The foregoing will show that the stepping notch cannot step the shaft back one notch before the motor starts. Actually, the normal stopping position of the motor will have the switch 5'! closed as the final stepping action of the stepping magnet will open the cam switches practically simultaneously with the final closing of the switch 51 and this deenergization of the motor circuit, to be described, will leave the field winding in circuit as a dynamic brake.

From the foregoing, it will be seen that when the knob I49 is depressed, and the shaft turned, a

circuit will be provided through the stepping magnet I59 only after the motor has started and has rotated a distance with the switch 5'! opened, and has subsequently closed the same. Consequently, operation of the stepping magnets depends upon rotation of the motor.

As previously noted, as soon as the switch 229 is released by release of the knob, the line 269 is connected to the battery. Rotation of the knob in the direction assumed, operates the cam switch I99 to close the contact I98 with the contact 290, but does not change the switch I9'I. This shifting of the switch I99 sends power through the motor rotor in one direction, it going from line 299 through the line 2'i5, the contacts 299 and I98, and the line Zlll to the limit switch Bl. both of the limit switches 89 and Ill will rest in the positions of Fig. 29. Consequently, the power from the line 2' passes through the limit switch 8|, the rotor 39, and the limit switch 99. From the latter, it flows through the line 28I and the switch I91 by contacts 2M and 292, line 214 to the line 265, which is permanently connected to ground, thus completing the circuit. This will cause the motor 39 to rotate in one direction. This rotation will operate the switch 51 in accordance with the number of flats on the shaft portion 55, and it will also operate the jack screw member 32 in one direction along the shaft. This displacement of the member 32 will move the tab 52 in one direction about its axis.

When the knob I49 rotates, it rotates the dial I38, and the angular distance, measured in terms of ultimate displacement of the tab 52, is shown by the final graduation on the dial that registers with the pointer I29. The pointer I42, having been displaced with the shaft I35, indicates the actual position of the tab at that time, as the pointer I42 maintains its original relationship to the dial. Thus, if the knob be turned clockwise in Fig. 19, the pointer I42 will also move clockwise to stay with the zero index on the dial. The relative movement of the pointer I29 relative to the dial is counterclockwise.

Thereafter, each time the switch 5'! closes, a current impulse will flow through the stepping magnet I59. This will cause return of the shaft toward neutral position in the amount of one tooth. The number of teeth here provided is such that this distance represents one half a degree of angular displacement of the trimmer tab- Normally,

Furthermore, the pointer I42 being fixed to the shaft I35 will return toward neutral position a corresponding amount. Since the zero position on the dial has been displaced clockwise, the counterclockwise return movement of the pointer I42 will cause this pointer to sweep across the dial counterclockwise so that it indicates on the dial at all times the actual position of the tab.

When finally the shaft is returned to neutral position, so that it returns its cam switches I96 and 294 to the position of Fig. 28, the motor circuit and the stepping magnet circuit will be broken. The motor will stop at once, because the shunt winding 25I is left in circuit and operates as a dynamic brake. Therefore, the pointer I42, having returned to its vertical position, will indicate on the dial, which remains displaced, that the trimmer tab has been moved the distance originally set by displacement of the dial with respect to the pointer I29.

The operation in the reverse direction is exactly symmetrical with the operation just described. It will be noted that when the switch I9! is shifted to close the contact 203, power runs from the line 266, through the line 216, switch i9 1, line 28I, limit switch 89, motor 39, limit switch 85, line 277, switch I96, and line 213 to the grounded line 265. This produces flow through the rotor in the direction opposite to that previously described, so that the motor operates in the other direction.

When the motor rotates to such an amount that one of the limit switches is opened and shifted to a ground connection, the result is that the 1* 1' motor circuit is broken on the power side of the rotor for the particular direction of rotation, but for rotation in the other direction, is grounded without having to pass through the motor cam switch which has been shifted.

Thus, in the original motor circuit, which ran from the line 266 through the line 215 to the switch I99, when the limit swtich 8| is opened by excessive rotation of the motor in the direction produced by this circuit, power never reaches the rotor. Also both sides of the rotor are grounded, the rotor circuit being broken from the power line, but extending from the ground line 219 through contacts 96 and 94 of the limit switch SI, through the rotor, through the contacts III and H2 of the limit switch 80, by line 28I, to contacts 20I and 202 of the switch I91 and thence by lines 214 and 265 to ground. This direct short circuit of the rotor circuit with the shunt winding remaining in circuit causes the motor to stop at once under the dynamic braking effect. Necessarily, the control also will stop.

When this occurs the dial I38 will be set to register some high calibration with the pointer I29. The pointer I42 will have moved counterclockwise in sweeping toward such calibration until it has approached the same, but it will be stopped prior to attaining the value. Thus, the shaft I35 is not likely to be very far from neutral position.

To illustrate, assume that the dial I38 has been turned until the pointer I29 registered with 15 up. The pointer I42 was stopped by the limit switch when it registered 13 up. The shaft I35 will be 2 out of neutral position.

If, then, the knob be depressed and the dial rotated counterclockwise until 13 registers with the pointer I29, such action will move the shaft I35 back 2 thus bringing it to neutral position. The pointer I42 will continue to register the 13 as it is displaced with the shaft. The whole anaemia 1:3 mechanism will remain stopped in this position determined by the limit switch.

If the. limit switch opened at. aninstant when the switch. 511 was. closed", one of. the: stepping magnets would." have been energized. However, thestoppage of movement of the pointer I 42 away fromiits neutral position would indicate an abnormal condition to the operator.

Such continued energization of one of the stepping coils would hold its extension against the teeth of the wheel I51 and prevent rotation there.- of. However, when the knob is depressed for resetting the control, the switch 221 is closed, connecting. therelay coil 225 150 ground. and. opening the switch 231 to release the stepping coil and thus to permit. free rotation of the dial. Of course, if the limit switch has actediatsome point ahead of the maximum dial position, in either. direction, any further displacement of the. dial in that direction will have no eifect.

The only way the motor can be restarted. is to displace the dial intne opposite direction any distance, returning toward zero or beyond. In short, the cam switches must be returned to neutral position and beyond; A's heretofore noted, merelyto return them to neutral position, so that both pointers 429 and I42 register the actual setting of the tab' on the dial, as determined" by the limit switch", will not change the tab setting at all. If, however, the dial is setback beyond this limit switch determination, the other set of cams will beclosed'. In the illustration mentioned, this will cause closure of the switches I91 and 205 while the switches 204 and H36 are in neutral position. In this case, the stepping'magr net circuit will be the same as if the limitswitches had not operated, but the motor circuit will comprise bringing power from the line 249 through the switch !91" in its upper position, through the limit switch 88, the rotor 39", and then the contacts 94 and 96 of the limit switch 8 i to ground. ihis renders the return'circuit ofth'e motor independent of the position of the switch i96' until the motor is moved to permit reclosure of the limit switch 8%. When such closure takes place, it occurs with asnap-action and the" motor will continue operation with the conventional circuit until the shaft [35" is returned to neutral position.

What is claimed is:

1. In a mechanism of'the kind described, a driven shaft, a motor fordriving'said shaft, and means to determine the number oi'rotations of the shaft'by controllingthe number of'rotations of the motor, said means comprising a control shaft adapted'for'movementtoward and'from a starting position, means to displace the shaft from starting position, a stepping magnet; armature-operated thereby, ZIldTXIIGHJIlS meve'd by movement of the armature to displace the shaft; for' operating the control shaft in a return; direction, means operated upon displacement: of the control shaft away from staitinggpositionsto effect. energization of the motor, meanslikewise operated: by displacement of the control shaft away from starting position ioreifecting acircuit for thestepping magnet, and means: operated by themot'or to make and break the stepping magnet circuit to effect periodical operation thereof to 'return'the shaft to starting position; and said motor and said stepplng'magmet'cirouit being deenergizedwhenthe control. shaft returns to starting position.

2; In amechanismrof. the kinddesoribed, a reversible-motor; a switch: means operated; inter..-

134 mittently by the motorduring operation thereof; a control ineansto preset the control a predetermineddistance in either direction from a neutral position; two stepping magnet means, one for returning. the control to neutral positionirom each direetiomof displacement, means in the control for determining-- which magnet meansshall be energized, .mea-ns in the: control foreffectingoporation of the motor in one direction upon displacementoiithe:control-in a first direction, and 1n'eans1-.in.the=' control for effecting operation of the in-otor'in t'here verse direction upon displacementtof-lthe control in the seconddirection, the switch..means being adapted to control the step.- ping: magnet means to effect a: predetermined number. of operations thereof per revolution of the motor, whereby the. direction and number of revolutions of the motor. may be determined by the. displacement otthe. control.

3...In. a. mechanism of. the hind described, a shunt woundirevensi'ble motor; switch means. op? erated thereby a predetermined number of times per revolution of'i thenrotor, a control .disp'laceable-selected distances in eitherdirection from-a neutral. position, means. in. the. control. to. effect energizatioirof thei motorrfor: rotation forward upon displ acement of. the. control. in 1 a first direction, andfor rotation backward upon displacemerit in: the; second. direction, said. means. being adapted to' 'stop operationof. the motorv when the control isin neutral'positi'on, a pair of. stepping magnets, and mechanism-operated by each. mag.- netfor acting uponthe control to. displace the same each timethe magnet. isimpulsed, there be.- ing. onev such magnet andv mechanism for returning; the control to; neutral position from each direction of. displacement, the extent of displacementdetermining, the number of irnpulses to the magnets. required to'efiect such return, the controlincluding. means effecting a'circuit for each stepping magnet when the control is displaced, and-for breaking: said circuits when the control is in neutral position, and said stepping magnet circuits including. said switch means, whereby the magnetsmay beimpulsed a predetermined number: of times for each motor revolution.

4-. In a mechanism of the kind described, a shunt wound reversible motor, switch means operated thereby apredetermined number of times per revolution oithe motor, a control displaceable selected distances in either direction from a neutral position, meansin'the control to eitect energization ofthe motor for rotation forward upon. displacement of the control in a first dis motion, and. for rotation backward upon displacement in. the second. direction, said means being:- ada-pted" to stop operation of the motor whenvthe control is' in neutral position, a pair of stepping magnets, and mechanism operated by eachmagnet; ioracting'upon the control toqdisplacethe same: each time the magnet isi-mpulsed, there being,- one. such magnet and mocha:- lllSifLiiOI" returning; th-econtrol to neutral position from each-direction ofdisplacement; the'ex tent ofi displacement determining the numberof impulses to' the. magnets required to effect such return; thescontrol including means effecting a circuit fior'eachstepping magnet when the control is displaced; and for breaking said circuits when the oontrolis in neutral position, andsaid stepping: magnet? circuits including said switch means; whereby the: magnets." may be" impulsed a predetermined" number-of" times for each: motor revolution, .an'do means to: prevent energizationi of a stepping magnet, upon displacement of the control, prior to starting of the motor.

5. In a mechanism of the kind described, a reversible mot-or, a forward circuit therefor, a reverse circuit therefor, a selector to close either circuit, said selector including a forward switch and means to shift the same from a first position to a second position when the selector is moved to forward position, and a reverse switch and means to shift the same from first to second position when the selector is moved to reverse position, the forward circuit including the forward switch in second position and the reverse switch in first position, and the reverse circuit including the reverse switch in second position and the forward switch in first position, and electrically operated means to return said selector to neutral position, and switch means causing said electrically operated means to operate when the selector is moved from neutral position and rendered inoperative when the selector is returned to neutral position.

6. In a mechanism of the kind described, a reversible motor, a forward circuit therefor, a reverse circuit therefor, a selector to close either circuit, said selector including a forward switch and means to shift the same from a first position to a second position when the selector is moved to forward position, and a reverse switch and means to shift the same from first to second position when the selector is moved to reverse position, the forward circuit including the forward switch in second position and the reverse switch in first position, and the reverse circuit including the reverse switch in second position and the forward switch in first position, and means to return said selector to neutral position, said means being caused to operate when the selector is moved from neutral position and rendered inoperative when the selector is returned to neutral position, said returning means including a forward return circuit and a reverse return circuit a forward return switch operated from first to second position when the selector is moved to a forward position, a reverse return switch operated from first to second position when the selector is moved to a reverse position, said forward return circuit including the forward in second position and the reverse return switch in first position, and said reverse return circuit including the reverse return switch in second position and the forward return switch in first position.

'7. In mechanism of the kind described, a motor, a control for determining the period of operation of the motor, said control including a control member and a preset member, the preset member being adapted to be moved from a starting position to a variable but selective position away from starting position, means causing the control member to be moved to restore the starting position, said means being responsive to power impulses and moved a given distance per power impulse, a circuit for the power-responsive means, a switch in the circuit, means operated by the motor to operate the switch a predetermined number of times for each rotation of the motor, means to prevent operation of the control during the presetting operation, comprising a switch in the control circuit, and means to open the switch during the presetting operation.

8. In a mechanism of the kind described, a motor, a control for determining the period of operation of the motor, said control including a control member and a preset member, the preset member being adapted to be moved from a starting position to a variable but selective position away from starting position, means causing the control member to be moved to restore the startmg position, said means being responsive to power impulses and moved a given distance per power impulse, a circuit for the power-responsive means, a switch in the circuit, means operated by the motor to operate the switch a predetermined number of times for each rotation of the motor, means to prevent operation of the control during the presetting operation, said means comprising a relay coil and switch, the switch being in the control circuit, and means operated by operation 1 the preset member to energize the coil and open the relay switch in the control circuit.

9. In a mechanism of the kind described, a motor, a control for determining the period of operation of the motor, said control including a control member and a preset member, the preset member being adapted to be moved from a starting position to a variable but selective position away from starting position, means causing the control member to be moved to restore the starting position, said means being responsive to power impulses and moved a, given distance per power impulse, a circuit for the power-responsive means, a switch in the circuit, means operated by the motor to operate the switch a predetermined number of times for each rotation of the motor, means to prevent operation of the control during the presetting operation, said means comprising a relay coil and switch, the switch being in the control circuit, means operated by operation of the preset member to energize the coil and open the relay switch in the control circuit, and a holding switch. closed upon energization of the coil and shunting the power-responsive means in its circuit to maintain the coil energized through the said parallel circuit until the motor switch opens to deenergize the coil.

10. In a mechanism of the kind described, a reversible motor, a field winding and a rotor winding therefor, a, forward circuit and a reverse circuit for the rotor winding, a control for determining the number of rotations of the motor, a forward limit switch operated after a maximum operation of the motor in a forward direction, a reverse limit switch operated after a maximum operation of the motor in a reverse direction, each limit switch having two poles and a single throw, the two motor circuits being interlocked and the control determining the direction of current flow therethrough from power source to return and each circuit including both limit switches in one position, and the limit switches being operable upon excess operation of the motor in their respective directions to short circuit the rotor circuits.

11. In a mechanism of the kind described, a motor, a control therefor, said control including a circuit for the motor, a reduction gearing in the motor, an operating shaft operated at reduced speed by the reduction gearing, said shaft having a threaded portion thereon, a nut on the threaded portion and movable from end to end thereof in accordance with the direction and number of rotations of the motor, limit switches in the motor circuit, and means movable by the nut when it approaches one end of the threaded portion to operate the limit switches and stop the motor, said means comprising a pivoted member disposed alongside the shaft with its pivot intermediate the ends of the shaft so that its ends may rock toward and, from the shaft, the side ofthepivoted member adjacent the shaft sloping outwardly from the pivot and toward the shaft to be ,en gageableby thenut atthe endsv of its travel on the shaft-and means onqthe pivotedmembento rat li it sw tch s when t pirete m mber is rocked by the nut.

e h n m ,theh nd descr bed, a e a l e e r ,sa dl Qntre revidine a circuit for the motor areduCfiQhfiearingin h m er nereti gzsh e erat dat reduced eedby h r et neie a;Sai shaft harms a threaded portion thereonra-nut on t-he threa ded or io an o l from en t end t ereo [in accordance with the direction andnuniber ef rotations of the motor, limit switches inthemotor ci c i means m v bl by the-nu Whene e proaches one end of the threadedportiqn to operatethe limit switch and stopzthe,motor, said means comprising a pivoted member disposed alongside the shaft withits pivot intermed I the ends of the shaft so-that; its ends may-reek mWh Yd 3 3d from h sh f nth 0 lth P QW member adjacent the .shaft sloping outwardly from the pivotandtowardthe'shaft to beachgageable by the nut at the ends of itstravel on the shaft, means on the piVQted member tb qperate the limit switches whenthepivoted member is rocked bythenut, and meansto preset' the limit switches relative to the pivoted memberlto adjust the position on the threaded portion reached by the nut when thelim'it switcheskare shifted. I A

'13. In a mechanism of,the kind described, ,a

control including shaft Q displaceable in opposite directions, electrical means ,to return the shaft, to startingpositiop, acam. on the ,shaft' a pair of oppositely facinglriseson thecam, a follower for each ,rise, said -f ollo,wers being ofi the rises when the shaft is in starting position, and onlyone of rthem being displaced npon a r-ise when the shaft is displaced in, eitherldiiiectionga swi o ra e breac e le n'en switehi eingfada pted to control the return means to effect; return of the shaftin one direction, and the eh beinea a e t eent elth l e nmx I effect retnrnof the shaft, in the. otherfdirectionfa reversible motor adapted to befqontrjolled' in,its operation by thecoritroL [third ,and iourt switches, one being operated each foil forward circuit for the motor, a reversei cireuft o t m t the t r v wit lhheihe edanteite control,the forwardcircuit forf I fou sw tc b n a ap ed cen re t. e e ci cuit fo h imqto 14. In a mechanism of the lgind described, a

co ro ine d nse sha t, la eabl lin,epnqslt directions, electrical means to return the shaft t sta e' i a am e rtheshe t. mi e le i fiaei is -en t e reamej e fd e for each rise, said followersbeing off the rises whenthe shaft is in starting positio'n andionly one of them being displacednriori arise when the shaft is displaced in either' directionfa switch operated by each followerfone switch being adapted to control the return meari's t'o effect-return of the shaft in one direction} and-thesecon'd being adapted tocontr lthe'returH m ansgwerfeet return of the shaftf in the other' direction, said return means comprising a'too'thed member and electrical means engagable-with the teeth-there- I of to returnthe sa'meto starting position,-said toothed member beingsecured-to" the Shaina setting member rotatable concentrically with the shaft, and axially displaceab'le 'relative to the shaft, engaging means fm-JcQnnecting ttxe toothed onl one o 18 tand setting 1 members .up on, axial, displacement of the; latter, whereby-rotation; of; the setting member will effect rotation of the shaft, and means to hold the;setting membemn position'to which it is rotated, .upen disen a m n of :th en in means. o,

' 1 5- i sen-m chanism o t kind es ri a centre in ludin -a; sheft snleeea n opp s dire ionsrei ctriealime h fiere u the sha to star n ;pcs. t, .n, .a=1eambn t e s a a pai p oppos tely facin ise th ea n, a follo e :fe erwhf-ris ,v said; iellewer i be e ,t el'ri en the-s af i r-i sta ing o t n, a onl on o them e nadise aeed up n a ris wh h..-the s aft isid sn a e z h;eith aii eet e ie wit o erated bY'wfifi-flh 1f01 DWQ YcQ1 B:- Wi C b i adap ed to contro lthel etu n; mean t fi e t n e the shaf iinen d rect on, a d th se n ei adan e tto con r here u meah l fi e a turn of tth sha inath oth dir tien Said, e-

tern tthesam --t. st rtin p sition said s membe l ei sec red t th et a se as memb ;ro atabl c n ri w the sha .;en xax liv dis ae ebl el v t the ft, eheas'nezreea sie ice ne t hs;t oot ed berwill effect rotation ofthe shaft, and means to hel th se tihememhe nt esi i to h ch i i rete ed e rd eheesemen .e e engaging me hstadialenth sett herm ansr fi e pointer ferlindi atihsath p si on t wh the d 1 h he nzseta ed ende r econ h iht s e to th d;;,reg i st ring with the dial to indicate ,the t h h.e r lat v t h d ;ln 5 meehan sh re th ki Vde h d a con i clu in =shei 1 di ee eb i eer 7 e tiops, electrical means to return the shaf t bett ,Q i i na e thes -aft, etnai ie tqe e. e-l fle ihsyr esc th camle icl ew iieneaa r s seida e w h e e the se w en tthe h i isinc e tingm it h and m beihs: ,i p ec ine e rise z h i s iae ,d ne then ir e en, a witch exerte b =.-e c .fe W ce wi bein adapt t cont th retur m ans to e iee t-return 9 the haf aen d re ti a the second being adapted-to eontr ol the-return m an .rt eiiee re urn-h 1 h sha t. n th other direction a r versibl ;;met9 adap e .t ih -eenrelle ii cmeret on; b h ;ce tr t d an teurtht wit he enebe ns op ated b c o ow a fcrwardei ei i lf rth m ter are e irc ihi rth me er th thi fl w t bein adapted to ,control the forward circuit for the motor, eandg-the fourth switch being adapted to control-gthet-reverse, circuitfor the; motor, said return meanswcomprisin'g a toothedmember and e eetricakm en sensaseabl with, h tee h th eof ;.to returnithe-same to. starting position, Said toqthedmember being .securedetoqthe, shaft, a setting member ,-rot atab1e concentrically with the shaft, and axially .displaceable relative to the shaft, engagingl-ineansgfor, connectingv the toothed andlsettin'g members upon axialdisplacement of the;iatter, whereby rotation of the setting-,member ,-.wi'l1 .efieet frotation .of the shaft, and means to 1- hold i the setting .member in position to which it: is rotatednpon disengagement of I the engaging means, i a member displaceab1eaxially relative to the" shaft, a e'fifth switch operated by displaceinentofsaidimemberfrom a firsttto a second position, A said ififthswitch ,in first position being 19 adapted to admit power to either motor circuit, and in its second position to ground the motor circuits.

1?. In a mechanism of the kind described, a control including a shaft displaceable in opposite directions, electrical means to return the shaft to starting position, a cam on the shaft, a pair of oppositely facing rises on the cam, a follower for each rise, said followers being off the rises when the shaft is in starting position, and only one of them being displaced upon a rise when the shaft is displaced in either direction, a switch operated by each follower, one switch being adapted to control the return means to effect return of the shaft in one direction, and the second being adapted to control the return means to effect return of the shaft in the other direction, a reversible motor adapted to be controlled in its operation by the control, third and fourth switches, one being operated by each follower, a forward circuit for the motor, a reverse circuit for the motor, the third switch being adapted to control the forward circuit for the motor, and the fourth switch. being adapted to control the reverse circuit for the motor, said return means comprising a toothed member and electrical means engageable with the teeth thereof to return the same to starting position, said toothed member being secured to the shaft, a setting member rotatable concentrically with the shaft, and axially displaceable relative to the shaft, engaging means for connecting the toothed and setting members upon axial displacement of the latter, whereby rotation of the setting member will effect rotation of the shaft, and means to hold the setting member in position to which it is rotated, upon disengagement of the engagin means, a member displaceable axially relative to the shaft, a fifth switch operated by displacement of said member from a first to a second position, said fifth switch in first position being adapted to admit power to either motor circuit, and in its second position to ground the motor circuits, and a sixth switch closed upon displacement of the axially displaceable member, a relay for controlling energization of the return means circuits, and said sixth switch being adapted to control energization of the relay, and a relay switch in said return means circuits opened upon energization of the relay.

18. A control device of the character described, comprising a mounting frame; a two direction selective adjustment means carried on the forward end of the frame, comprising a rotatable knob assembly, means normally locking the assembly against rotation in the frame and disengageable upon limited axial movement of the assembly in said frame, a main switch mounted on the frame and connected in an electrical control circuit; and an axially shiftable shaft sup ported on the frame with one end disposed in operative engagement with the switch, said shaft being adapted to assume either of two axial positions of adjustment and adapted in one position to have its other end positioned to be engaged by the knob assembly, incident to such limited axial movement of the latter, for axially shifting the shaft to its other position of adjustment for effecting actuation of said switch.

19. A preselector for controlling the movement and positioning of electric power operated apparatus within a predetermined range of movement, comprising a mounting frame; a two direction stepper mechanism mounted on the frame and comprising a rotatable stepper gear adapted to normally assume a zero starting position, a pair of electromagnets adapted to be selectively operated by impulses of electric current and stepper fingers associated with said magnets for operating said gear in step-by-step manner; a dual set of normally open switch means for each electromagnet mounted on said frame, each of said switch means including a switch in circuit with a corresponding magnet and a switch in circuit with the power operated apparatus; a two direction selective adjustment means adapted to be moved from a zero starting position to a position corresponding to a position to be assumed by said apparatus, within its range of movement; disengageable driving connections for causing rotative movement of said gear to a position in correspondence to the adjusting movement of said adjustment means; means under control of said gear and operable, upon completion of adjustment of said adjustment means for rendering operative a corresponding pair of switches of one of said dual set of switch means, to complete two branch electric circuits to a corresponding electromagnet and said power operated apparatus to cause said electromagnet to move said gear in step-by-step manner to its zero starting position and simultaneously cause said apparatus to be moved in synchronism with said gear to a preselected position of adjustment, said last mentioned means being responsive to the movement of said gear and adapted when said gear arrives at its zero starting position to cause opening of said two switches for breaking the electric circuits to said corresponding magnet and said power operated apparatus; and electrically operated control means connected in circuit with said magnets for insuring and maintaining correspondence in positioning of said apparatus with said preselected adjustment of the adjustment means.

20. A preselector for controlling the movement and positioning of electric power operated apparatus within a predetermined range of movement, comprising a mounting frame; a two direction. stepper mechanism mounted on the frame and comprising a rotatable stepper gear adapted to normallyassume a zero starting position, a pair of electromagnets adapted to be selectively operated by impulses of electric current and stepper fingers associated with said magnets for operating said gear in step-by-step manner; a dual set of normally open switch means for each electromagnet mounted on said frame, each of said switch means including a switch in circuit with a corresponding magnet, and a switch in circuit with the power operated apparatus; a two direction selective adjustment means adapted to be moved from a zero starting position to a position corresponding to a position to be assumed by said apparatus, within its range of movement; disengageable driving connections for causing rotative movement of said gear to a position in correspondence to the adjusting movement of said adjustment means; means under control of said gear and operable, upon completion of adjustment of said adjustment means for rendering operative a corresponding pair of switches of one of said dual set of switch means, to complete two branch electric circuits to a corresponding electromagnet and said power operated apparatus to cause said electromagnet to move said gear in step-by-step manner to its zero starting position and simultaneously cause said apparatus to be moved in synchronism with said gear to a preselected position of adjustment, said-last mentioned means being responsive to the movement of said gear and adapted when said gear arrives at its zero starting position to cause opening of said two switches for breaking the electric circuits to said corresponding magnet and said power operated apparatus; and electrically operated control means connected in circuit with said magnets for insuring and maintaining exact correspondence in positioning of said apparatus with said preselected adjustment of the adjustment means, said last mentioned control means comprising a relay, and a normally open switch con nccted in circuit with the coil of the relay and adapted to be closed incident to adjusting movement of the adjustment means for maintaining correspondence in movement of the stepper gear and the apparatus being controlled.

21. A preselector for controlling the movement and positioning of electric power operated apparatus within a predetermined range of movement, comprising a mounting frame; a two direction stepper mechanism mounted on the frame and comprising a rotatable stepper gear adapted-to normally assume a zero starting position; a pair of electromagnets adapted to be selectively operated by impulses of electric current and stepper fingers'associated with said magnets for operating said gear in step-by-step manner; a dual set of normally open switch means for each electromagnet mounted on said frame, each of said switch means including a switch in circuit with a corresponding magnet and a switch in circuit with the power operated apparatus; a two direction selective adjustment means adapted to be moved from a zero starting position to -a position corresponding to a position to be assumed by said apparatus, within its range of movement; disengageable driving connections for causing rotative movement of said gear to a position in correspondence to the adjusting movement of said adjustment means; means under control of said gear and operable, upon completion oi adjustment of said adjustment means for rendering operative a corresponding pair of switches of one of said dual set of switch means, to complete two branch electric circuits to a corresponding electromagnet and said power operated apparatus to cause said electromagnet to move said gear in step-by-step manner to its zero starting position and simultaneously cause said apparatus to be moved in synchronism with said g ear'to a preselected position of adjustment, said last mentioned means being responsive to the movement of said gear and adapted when said gear arrives at its zero starting position to cause opening of said two switches for breaking the electric circuits to said corresponding magnet and said power operated apparatus; and electrically operated control means connected in circuit with said magnets for insuring and maintaining exact correspondence in positioning of said apparatus with said preselected adjustment of the adjustment means, said last-mentioned means comprising a relay, a normally open switch connected in circuit with the coil of the relay and adapted to be closed incident to adjusting movement of the adjusting means for temporarily opening the circuit including said magnets for maintaining correspondence in movement of the stepper gear and the apparatus being controlled, and a switch connected in said branch circuits for'the power operated apparatus and adapted to open said branch circuits incident to adjusting movement of said adjusting means.

22. A preselector for controlling the movement and positioning of'electric power operatedap-'- paratus within a predetermined range of movement, comprising a mounting frame; a two direc' tion stepper mechanism mounted on the frame and com-prising a rotatable stepper gear adapted to normally assume a zero starting'position, a pair of electromagnets adapted to"be selective1yoperated byimpulses of electric current and stepper fingers associated with said magnets for" operating said gear in step-by-step manner; a dual set of normally open switch means for each electromagnet mounted on said frame, each of said switch means including a switch in circuit with a correspondin magnet and a switch in circuit with the power operated apparatus a two. direction selective adjustment means adapted tobe moved from a zero starting position to a position correspondin to a position to be assumed" by said apparatus, within its range of movement disengageable driving connections for causing rotative movement of said gear to a position'in correspondence to the adjusting movement of said adjustment means; means under control-of; said gear and operable, 'upon completion"ofad-* justment of said adjustment means'fo r rendering operative a corresponding pair of switches of 'one' of said dual set of switch means, to complete two branch electric circuits to a correspondin electromagnet and said power operated apparatus tocause said electromagnet to move said gear in step-by-step manner to its zero starti-ng' 'rjosition;

and simultaneously cause said apparatus tobe' moved in synchronism'with'said gear to afpreselected position of'adjustment, said last men-- tioned means bein respo'nsive to the movement of said gear and adapted when said'gear arrives at its zero starting position to cause opening of said two switches for breaking the electric cir-- cuits to said corresponding magnet and' saidpower operated apparatus; and electrically operated control means connected in circuit with; said magnets for insuring and maintaining exact correspondence in positioning oi said'apparatuswith said preselected adjustment of the adjust? ment means, said last-mentioned means com prising a relay, a normally open switch connected in circuit with the coil of the relay and adapted to be closed incident to adjustingmovem'entof the adjusting means for temporarily opening the circuit including said magnets for maintainingcorrespondence in movement of thestepper'gear and the apparatus being controlled, and a switch connected in said branch circuits for thepower operated apparatus and adapted to open said branch circuits incident to adjusting movement of said adjusting means, said last' mentioned switch and the-switch connected in circuitwi-th" said relay being positioned relativelytoeaitah other for causing'actuation'of one" incidentto: actuation by the'o'ther 23. Apreselectorfor controlling themcvement" and positioning ofreniotely located "electric power operated apparatus within a predetermined range of movement, coinprising' a mounting frame;' a two direction stepper mechanism mounted on the -frameand adapted to" be operated by pulsations of electric cur-rent, anticomprising a rotary stepp r gear normally disposed in a zero starting position; a two direction selective adjustment means'ca'rried on the'frameand adapted to be-movedfrom' a 'zero starting" position, in either direction, to a position cor; responding to a position to which said apparatus" is to'be moved, within itsrangeof movement;

said adjusting means and gear including disen gageable interconnections to cause movement of said gear incident to adjustment of said adjusting means; and means on the frame, including means operably connected to said gear, and rendered operable incident to completion of adjustment of said adjustment means for completing interconnected electric control circuits for operating said stepper gear to assume its zero starting position and simultaneously moving said apparatus to a position, within its range of movement, corresponding to the said adjustment of said selective adjustment means.

. 24. A preselector for controlling the movement and positioning of remotely located electric power operated apparatus within a predetermined range of movement, comprising a mounting frame; a

tvvo direction stepper mechanism mounted on theframe and adapted to be operated by pulsations of electric current, and comprising a rotary stepper gear normally disposed in a zero starting position; a two direction selective adjustment means carried on the frame and adapted to be moved from a zero starting position, in either direction, to a position corresponding to a position to which said apparatus is to be moved, within its range of movement; said adjusting means and gear including disengageable interconnections to cause movement of said gear incident to adjustment of said adjusting means; means on the frame, including means operably connected to said gear, and rendered operable incident to completion of adjustment of said adjustment means for completing interconnected electric control circuits for operating said stepper gear to assume its zero starting position and simultaneously moving said apparatus to a position, within its range of movement, corresponding to the said adjustment of said selective adjustment means, a graduated scale and index means associated with said adjustment means and the frame to visually indicate the position of adjustment to be assumed by said apparatus, within its range of movement; and means rigidly associated andmovable with said stepper gear including an indicating feature for cooperating with said scale and index means to visually indicate at all times the exact position of adjustment of said gear.

25. A preselector for controlling the movement and positioning ofremotely located electric power operated apparatus Within a predetermined range of movement, comprising a mounting frame a two direction stepper mechanism mounted on the frame and adapted to be oper ated by pulsations of electric current, and comprising a rotary stepper gear normally disposed in a zero starting position; a two direction selective adjustment means carried on the frame and adapted to be moved from a zero starting position, in either direction, to a position corresponding to a position to which said apparatus is to be moved, within its range of movement; said adjusting means and gear includin disengageable interconnections to cause movement of said gear incident to adjustment of said adjusting means; and means on the frame, including means operably connected to said gear, and rendered operable incident to completion of adjustment of said adjustment means for completing interconnected electric control circuits for operating said stepper gear to assume its zero starting position and simultaneously movin said apparatus to a position, within its range of movement, corresponding to the said adjustment of said selective adjustment means, said last mentioned means including a control cammovable with said gear and adapted to render said cir-- cuits inoperative when said gear returns to its.

the frame, comprising a rotatable knob assembly mounted coaxially with the stepper gear, and index means associated with the knob assembly and frame, said knob assembly andaportionof the-index means being axially shiftable toward and away from said stepper gear and rotatable in either direction, when shifted toward said stepper gear, from a zero starting position toa preselected position corresponding to a position to which said apparatus is to be moved, within its range of movement; driving connections for causing locking engagement of said knob assembly and stepper gear incident to axial movement of said knob assembly for effecting rotative adjustment of the stepper gear incident to rotation of the knob assembly to a predetermined position; spring means for axially shifting said knob assembly to disengage said drivin connections with the stepper gear; and means carried by the frame and connected to said stepper gear and operable, when said stepper gear is moved to an adjusted position and is disengaged from the knob assembly, for completing interconnected electric control circuits for moving said stepper gear to its zero starting position and simultaneously moving said apparatus to a position, within its range of movement, corresponding to the position of adjustment imparted to said stepper gear by said knob assembly.

27. A preselector for controlling the movement and positioning of remotely located electric power operated apparatus within a predetermined range of movement, comprising a mounting frame; a two direction stepper mechanism carried on the frame and adapted to be selectively operated by pulsations of electric current, and comprising a rotary stepper gear normally disposed at a zero starting position; a two direction selective adjustment means carried on the frame, comprising a rotatable knob assembly, and a selector gear mounted coaxially with the stepper gear, and index means associated with the knob assembly and frame, said knob assem-,

bly and selector gear being axially shiftable toward the stepper gear and rotatable in either direction, in such shifted position, from a zero starting position to a preselected position corresponding to a position to be assumed by said apparatus, within its range of movement; locking means on the frame engageable with said selector gear to normally preclude rotation thereof and the knob assembly, and disengageable upon axial movement of said knob assembly and selector gear toward said stepper gear to permit rotative adjustment thereof; driving means for interconnecting said gears in such shifted position whereby said stepper gear is caused to be rotated with the selector gear to a preselected positi-on;'

spring means for urging the knob assembly and selector gear to its outer position to disengage said driving means, means carried by the frame and connected to said stepper gear for rotation therewith and adapted when the stepper gear is disengaged from the selector gear for completing interconnected electric control circuits for moving said stepper gear to its zero starting position and simultaneously moving said apparatus to a position, within its range of movement, corresponding to the preselected position of adjustment of said knob assembly, said last mentioned means being constructed and arranged to open said interconnected circuits when said stepper gear arrives at its zero starting position, and simultaneously arresting said apparatus at its preselected position of adjustment; and a main switch connected in said control circuits adapted to be moved to open position incident to axial movement of the knob assembly toward the stepper gear and adapted to assume a closed position after said knob assembly is moved axially away from the stepper gear.

28. A preselector for controlling the movement and positioning of remotely located electric power operated apparatus within a predetermined range of movement, comprising a mounting frame; a two direction stepper mechanism carried on the frame and adapted to be selectively operated by pulsations of electric current, and comprising a rotary stepper gear normally disposed at a zero starting position; a two direction selective adjustment mean carried on the frame, comprising a rotatable knob assembly, and a selector gear mounted coaxially with the stepper gear, and index means associated with the knob assembly and frame, said knob assembly and selector gear being axially shiftable toward the stepper gear and rotatable in either direction, in such shifted position, from a zero starting position to a preselected position corresponding to a position to be assumed by said apparatus, within its range of movement; driving means for interconnecting said gears in such shifted position whereby said stepper gear is caused to be rotated with the selector gear to a preselected position; spring means for urging the knob assembly and selector gear to its outer position to disengage said driving means; a springpressed detent engaging the teeth of said stepper gear to insure uniform step-by-step actuation; and means carried by the frame and connected to said stepper gear for rotation therewith and adapted when the stepper gear is disengaged from the selector gear for completing interconnected'electric control circuits for moving said stepper gear to its zero starting position and simultaneously moving said apparatus to a position, within its range of movement, corresponding to the preselected position of adjustment of said knob assembly.

CLINTON H. DEDERICK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 613,869 Russell Nov. 8, 1898 835,382 Willard Nov. 6, 1906 999,947 Barnum Aug. 8, 1911 1,304,269 Dawson et al May 20, 1919 1,311,784 White July 29, 1919 1,508,796 Kaminski Sept. 16, 1924 1,610,080 Eaton Dec. 7, 1926 1,725,772 Waite et a1 Aug. 27, 1929 1,728,759 Higbee Sept. 17, 1929 1,782,907 Nielsen Nov. 25, 1930 2,069,516 Baker Feb. 2, 1937 2,090,812 schmitt Aug. 24, 1937 2,382,985 Bullen Oct. 26, 1943 2,355,381 Lear Aug. 8, 1944 FOREIGN PATENTS Number Country Date 452,872 France May 24, 1913 

